A new method of summing crosstalk from mixed sources: the generalized FSAN method

Digital subscriber lines (DSL) are fundamentally limited by crosstalk. The case where all crosstalk is from the same type of DSL has been studied over the years and accurate models have been standardized. However, crosstalk from multiple different types of DSLs is a relatively new area of study and models of summing mixed crosstalk have only recently been postulated. In this contribution, a new method of summing crosstalk due to mixed sources is proposed. This new method consists of deriving lower bounds to the worst-case method, which is intrinsically too pessimistic. It has been ascertained that the exploitation of the Minkowski inequality yields a new model that exhibits appealing properties. Moreover, it is shown here for the first time that the FSAN method is a particular case of the Minkowski-bound method and not, as previously believed, a method with no “physical justification or mathematical soundness.” Finally, simulation results that confirm the effectiveness of this new method are presented.